This invention relates to procedures for identifying a risk of a collision and for avoiding collisions in aviation.
The TCASII (Traffic Collision Avoidance System) for the avoidance of collisions has become known and is described, for example, in the FAA Document, Reprint by BFS, "TCASII System Description", Washington, D.C., USA 1993. The equipping of all aircraft comprising more than thirty seats which are authorised in the USA with this system has been prescribed in the USA since 1993. It provides the pilots of aircraft with a direct warning of possible conflicts with other aircraft in the vicinity. Independently of the ground control and of the visibility conditions, the pilot of the aircraft is provided with the possibility of recognising potential conflicts in good time and of reacting to them. The algorithm which forms the basis of TCASII is not intended for the purpose of controlling normal aviation traffic. It is simply intended to avoid a collision in the event of inappropriate behaviour by aviation participants or by ground control.
This algorithm is based on the TAU criterion, which determines the relative time of approach of two aircraft up to the time of the nearest approach. For this purpose, the transponders of the aircraft involved are repeatedly and actively interrogated. The time to the furthest approach is then calculated for constant flying behaviour. If a defined time threshold up to the furthest approach is undershot, the system reacts and proposes a vertical evasive manoeuvre to the pilot of the aircraft.
In the vicinity of the ground, the operation of TCAS is limited, and TCAS cannot be used for traffic taxiing on the ground. Moreover, vertical evasive manoeuvres are not in accordance with recognised evasive rules. For the vertical evasive manoeuvres which are proposed, there is the risk of flying through other flying levels and of endangering other participants in air traffic.
The underlying object of the procedure according to the invention is to provide the pilot with a visualisation, in an illustrative manner, of conflict potentials which actually exist, so that the pilot can make safe decisions regarding evasive routes. Apart from the detection of the conflict potential which actually exists, the object is also to make possible the automatic proposal of evasive routes without further risks arising at the same time.
In one procedure for identifying a risk of a collision, the object according to the invention is achieved in that for each aircraft concerned, probabilities are calculated with which the aircraft will be situated in predetermined space elements at a plurality of selected times (occupancy probabilities), and that from the occupancy probabilities of the aircraft concerned and the occupancy probabilities of other objects, the probabilities of the simultaneous occupancy of each space element by the aircraft concerned and by at least one of the other objects (collision probabilities) are calculated for the predetermined space elements and the selected times.